1. Field of the Invention
The present invention relates to a development apparatus of a liquid electrophotographic printer, and more particularly, to a development apparatus of a liquid electrophotographic printer in which the boundary portion between an image area of a photoreceptor web and a non-image area of an edge portion is prevented from being contaminated.
2. Description of the Related Art
Referring to FIG. 1, a typical liquid electrophotographic printer includes a photoreceptor web 10 circulating while being supported by a plurality of support rollers (not shown). The photoreceptor web 10 has an image area D.sub.1 corresponding to a development roller 11 to which a development electrical potential V.sub.D of a predetermined level is applied during development, and a non-image area D.sub.2 provided at both edge portions of the image area D.sub.1.
The photoreceptor web 10 is initialized as the entire surface thereof is charged to an electrical potential V.sub.0. A laser scanning unit (LSU)(not shown) scans light to the photoreceptor web 10 according to image signals so that a portion of the image area D.sub.1 is charged to an image electrical potential V.sub.I to form an electrostatic latent image area D.sub.1 '.
The electrostatic latent image area D.sub.1 ' is developed as it passes the development roller 11. That is, developer adhering to the outer circumferential surface of the development roller 11 is transferred to the photoreceptor web 10 due to the difference in electrical potential between a development electrical potential V.sub.D of the development roller 11 and the image electrical potential V.sub.I of the photoreceptor web 10 so that an electrostatic latent image is developed. Developer in the electrostatic latent area is pressed by a squeegee roller 13 so that toner of the developer becomes filmy and the other liquid carrier is removed from the photoreceptor web 10.
Here, the development roller 11 constantly maintains the development electrical potential V.sub.D. Thus, as the development roller 11 and the image area D.sub.1 of the photoreceptor web 10 having different electrical potential levels face each other, the electrical potential V.sub.O of the image area D.sub.1 is changed to a balanced electrical potential V.sub.E according to the charge balance principle as shown in the drawing. Such a state causes a difference in electrical potential at a boundary line A between the image area D.sub.1 and the non-image area D.sub.2, that is, both edge portions of the image area D.sub.1 are developed by the developer remaining on the photoreceptor web 10. Thus, the developer at the boundary line A is pressed by the squeegee roller 13 and firmly remains on the photoreceptor web 10, to thus contaminate the photoreceptor web 10.